Rapid deterioration in buried leather: archaeological implications

Area of Science:

• Archaeological science
• Materials science
• Biochemistry

Background:

• Archaeological leather degradation impacts understanding of historic communities.
• Burial conditions pose significant risks to leather preservation.
• Vegetable-tanned leather's long-term survival is influenced by complex degradation and preservation processes.

Purpose of the Study:

• To investigate the survival, destruction, and preservation mechanisms of vegetable-tanned leather.
• To analyze chemical changes in leather following experimental burial and in archaeological contexts.
• To compare FTIR-ATR data from experimentally buried and archaeological leather samples.

Main Methods:

• Non-destructive Fourier-transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy was applied.
• Experimentally buried vegetable-tanned leather and archaeological leather from Vindolanda, UK were analyzed.
• Changes in chemical functional groups of tannins, collagen, and lipids were monitored.

Main Results:

• Rapid changes, likely microbial, targeted lipids but not collagen in experimentally buried leather.
• FTIR-ATR spectra indicated rapid de-tanning in wet soil, making archaeological leather resemble untanned samples.
• Vegetable tanning promoted long-term leather preservation in wet soil despite de-tanning.

Conclusions:

• FTIR-ATR analysis effectively revealed destructive de-tanning in waterlogged environments.
• The vegetable-tanning method is crucial for long-term leather preservation in wet burial conditions.
• Mineral components and sample heterogeneity are important factors influencing leather degradation and preservation, requiring consideration within larger datasets.